The Patent Laying-Open Gazette No. Hei. 4-267727 discloses a multi-layered container designed such that ambient air is inhibited from entering the container through a mouth while allowing its content to be discharged by the pumping action of an inner and outer layers. This container consists of a bottle and a cap, wherein the bottle is composed of the impermeable inner layer and the squeezable outer layer, with the cap being attached to the mouth part of the bottle. The inner layer can be readily delaminated from the outer layer in which at least one ventilation hole is formed such that the ambient air can communicate with a space between the layers. A check valve is incorporated in connection with the ventilation hole. The cap has a discharging outlet and a further check valve cooperating therewith.
Therefore, the inner layer will spontaneously shrivel as quantity of the content decreases, with the ambient air flowing into the space through the at least one ventilation hole so that only the outer layer can restore and always maintain its normal configuration. Its content remains satisfactory in quality, from the beginning to end of use, without being adversely affected by ambient air or external light beams.
The multi-layered container in the prior art has a film tag adhered in part to the rim of the ventilation hole, and the tag larger than the hole is disposed inside the outer layer so as to serve as a valve body in a ventilation valve. Such a kind of ventilation valve will allow air to flow only inwardly into the container from outside. When a user grips the container having a decreased amount of content left therein, the ventilation hole will be closed with the valve body due to an increasing inner pressure between the layers so as not to allow any amount of air to leak out from the interlayer space. Thus, such a depressed outer layer will compress air present between the layers, thereby causing the compressed interlayer air to press in a centripetal direction the inner layer to be capable of exuding the content out of the container to the very end.
The prior art method may comprise the steps of preliminarily blow molding or thermally forming the outer layer that has the ventilation hole formed therein, and subsequently integrating it with the inner layer. However, such a method requires so many steps as raising manufacture cost of the discharging containers and lowering yield thereof.
Therefore, an object of the present invention is to provide a discharging container having at least one ventilation hole but lacking in any valve body in connection therewith, nevertheless allowing ambient air to flow into the interlayer space and ensuring exhaustion of the liquid content. Thus, the invention aims at simplifying a structure of the container and lowering its manufacture cost.